Many mobile communication devices such as phones, tablets, and phablets are equipped with high-speed links capable of providing high definition video and/or high data-rate storage. The use of more sensitive, wide-band, and/or smart antennas in these communication devices is becoming more and more widespread. The higher sensitivity and the broader bandwidth of these antennas make them more susceptible to electro-magnetic interference (EMI), in particular, the EMI noise generated by various circuitry of the communication device itself.
For example, the EMI noise generated by a display driver or a power-management integrated circuit (PMIC) of a mobile communication device can cause ˜3 dB broadband noise in a frequency band of a wireless communication protocol (e.g., LTE, Wi-Fi, or Bluetooth) which can lead to dropped calls or reduced connectivity. When the noise source is far from the RF ground, filtering the noise by decoupling capacitors connecting noisy traces to ground is not an option. Therefore, as the noise travels through the exposed flex traces, it radiates to the antennas, causing desense.